Porous ceramics can easily breed bacteria, good and bad. And glazes on ceramics can contain all kinds of delightful compounds that can leach out. You certainly don’t want to eat or breathe unfired glaze.

As for ceramic nonstick cookware, I’m not convinced that such a thing exists. I think that “ceramic” coatings are actually sol-gel, and I can’t find a straight answer as to what is in them. They do advertise that they are fluoropolymer-free, and they seem to be stable to rather higher temperatures than PTFE.